Zero hours - Motorway Plane disaster - Kegworth air Flight 92

The Kegworth air disaster occurred when a Boeing 737-400 crashed on to the embankment of the M1 motorway near Kegworth, Leicestershire, England, while attempting to make an emergency landing at East Midlands Airport on 8 January 1989. British Midland Flight 92 was on a scheduled flight from London Heathrow Airport to Belfast Airport, when a fan-blade broke in the left engine, disrupting the air conditioning and filling the flight deck with smoke. The pilots believed that this indicated a fault in the right engine, since earlier models of the 737 ventilated the flight-deck from the right, and they were unaware that the 400 used a different system. The crew mistakenly shut down the good engine, and pumped more fuel into the malfunctioning one, which burst into flames. Of the 126 people aboard, 47 died and 74 sustained serious injuries. The inquiry attributed the blade fracture to metal fatigue, caused by heavy vibration in the newly upgraded engines, which had only been tested in the laboratory and not under representative flight conditions. After taking off from Heathrow at 19:52, Flight BD 092 was climbing through 28,300 feet to reach its cruising altitude of 35,000 feet when a blade detached from the fan of the port (left) CFM International CFM56 engine. While the pilots did not know the source of the problem, a pounding noise was suddenly heard, accompanied by severe vibrations. In addition, smoke poured into the cabin through the ventilation system and a burning smell entered the plane. Several passengers sitting near the rear of the plane noticed smoke and sparks coming from the left engine. The flight was diverted to nearby East Midlands Airport at the suggestion of British Midland Airways Operations. After the initial blade fracture, Captain Kevin Hunt had disengaged the plane's autopilot. When Hunt asked First Officer David McClelland which engine was malfunctioning, McClelland replied: "It's the left.... It's the right one". In previous versions of the 737, the left air conditioning pack, fed with compressor bleed air from the left (number 1) engine, supplied air to the flight deck, while the right air conditioning pack, fed from the right (number 2) engine supplied air to the cabin. On the 737-400 this division of air is blurred; the left pack feeds the flight deck but also feeds the aft cabin zone, while the right feeds the forward cabin. The pilots had been used to the older version of the aircraft and did not realise that this aircraft (which had only been flown by British Midland for 520 hours over a two-month period) was different. The captain later claimed that his perception of smoke as coming forward from the cabin led them to assume the fault was in the right engine. The pilots throttled back the working right engine instead of the malfunctioning left engine. They had no way of visually checking the engines from the cockpit, and the cabin crew — who did not hear the commander refer to the right hand engine in his cabin address — did not inform them that smoke and flames had been seen from the left engine. When the pilots completely shut down the right engine, they could no longer smell the smoke, which led them to believe that they had correctly dealt with the problem. As it turned out, this was a coincidence: when the autothrottle was disengaged to shut down the right engine, the fuel flow to the left engine was reduced, and the excess fuel which had been igniting in the jet exhaust disappeared; therefore, the ongoing damage was reduced, the smoke smell ceased, and the vibration reduced, although it would still have been visible on cockpit instruments. During the final approach to the East Midlands Airport, more fuel was pumped into the damaged engine to maintain speed, which caused it to cease operating entirely and burst into flames. The flight crew attempted to restart the right engine by windmilling, using the air flowing through the engine to rotate the turbine blades and start the engine, but the aircraft was by now flying at 185 km/h (115 mph), too slow for this. Just before crossing the M1 motorway at 20:24:43, the tail struck the ground and the aircraft bounced back into the air and over the motorway, knocking down trees and a lamp post before crashing on the far embankment and breaking into three sections approximately 475 metres (519 yd) short of the active runway's paved surface and approximately 630 metres (689 yd) from its threshold. (pp6–7) Remarkably, there were no vehicles travelling on that part of the motorway at the moment of the crash.